AI and cognitive psychology rant (getting more and more OT - tell me if I should shut up)

Michele Simionato mis6 at pitt.edu
Sun Nov 2 07:19:11 CET 2003


Stephen Horne <steve at ninereeds.fsnet.co.uk> wrote in message news:<uhe2qv0gff8v17trs4cj6mg88t2o7smq9b at 4ax.com>...
> On 29 Oct 2003 23:26:05 -0800, mis6 at pitt.edu (Michele Simionato)
> wrote:
> >I have got the impression (please correct me if I misread your posts) that
> >you are invoking the argument "cats are macroscopic objects, so their
> >ondulatory nature does not matter at all, whereas electrons are
> >microscopic, so they ondulatory nature does matter a lot."
> 
> That is *far* from what I am saying.
>
Oops, sorry! I was not sure about your point: sometimes I have difficulties 
in understanding what are you saying, but when I understand it, I usually agree 
with you ;)
 
> The evidence suggests that conscious minds exist
> within the universe as an arrangement of matter subject to the same
> laws as any other arrangement of matter.

I think that mind is a an arrangement of matter, too; nevertheless, 
I strongly doubt that we will ever be able to understand it. Incidentally,
I am also quite skeptical about IA claims.

> I prefer Penrose' theory

I read a Penrose's book book years ago: if I remember correctly, he
was skeptical about AI (that was ok). However, at some point there was
an argument of this kind: we don't understand mind, we don't  understand
quantum gravity, therefore they must be related. (?) 

> most current theory is so
> abstract that the explanations should be taken as metaphors rather
> than reality anyway.

True.

> No problem with that, but we are seeing microscopic effects en masse
> rather than macroscopic effects - something rather different, in my
> mind, to a cat being both alive and dead at the same time. 

> The effects
> when they occured were on the microscopic scale - only the artifacts
> are macroscopic.

I have nothing against what you say in the rest of your post, but let me
make a comment on these points, which I think is important and may be of
interest for the other readers of this wonderfully off-topics thread.

According to the old school of Physics, there is a large distinction
between fundamental (somewhat microscopic) Physics and
non-fundamental (somewhat macroscopic) Physics. The idea
is that once you know the fundamental Physics, you may in principle
derive all the rest (not only Physics, but also Chemistry, Biology,
Medicine, and every science in principle). This point of view, the
reductionism, has never been popular between chemists of biologists, of 
course, but it was quite popular between fundamental physicists with
a large hubrys.

Now, things are changing. Nowadays most people agree with the effective 
field theory point of view.  According to the effective field theory approach,
the fundamental (microscopic) theory is not so important. Actually, for
the description of most phenomena it is mostly irrelevant. The point is
that macroscopic phenomena (here I have in mind (super)conductivity or
superfluidity) are NOT simply microscopic effects en mass: and in
certain circumstances they do NOT depend at all from the microscopic theory.

These ideas come from the study of critical phenomena (mostly in condensed
matter physics) where the understanding of the macroscopic is (fortunately) 
completely unrelated from the understanding of the microscopic: we don't need 
to know the "true" theory or a detailed description of the material we
are studying, if we are near a critical point. In this situation it is enough to
know an effective field theory which can explain all the phenomena we can see 
given a finite experimental precision, even if it is not microscopically
correct. In critical phenomena the concept of universality came out: completely 
different microscopical theories can give the *same* universal macroscopic 
field theory. Actually, the only things that matter are the dimensionality 
of the space-time  and the symmetry group, all others details are irrelevant.

This point of view has become relevant at the fundamental Physics level too, 
since nowadays most people regard the Standard Model of Particle Physics 
(once regarded as "the" fundamental theory) as a low energy effective 
theory of the "true" theory.

This means that even if it is not the full story, it explain the 
99.99% of phenomena we can measure; moreover, it is extremely 
difficult to see clear signatures of the "true" underlining theory.
The real theory can be string theory, can be loop quantum gravity,
can be a completely new theory, but for 99.99% of our experiments
only the effective theory matters. So, even if we knew perfectly
quantum gravity, this would not help at all in describing 99.99% 
of elementary particle physics, since we would still need to
solve the quantum field theory. 

And, for a similar reason, even if we knew everything about QCD, 
we could not use it to describe the wheather of Jupiter (which is described 
by a completely different effective theory) even if we had an ultra-powerful
Python-powered quantum computer ...

That's life, but it is more interesting this way ;)


              Michele




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